Sodium lauryl sulfate (SLS) is used in almost every commercial soap, shampoo, hand and face wash as a detergent and foaming agent.
Did you know that SLS is also a petroleum based surfactant used in industrial car washes, floor cleaners and engine degreasers because it cuts through and dissolves grease and oil? Yes, that’s grease in car engines! What’s it doing in your soap and shampoo? Well SLS does clean…harshly. But perhaps the main reasons big companies use SLS are because it creates foam and is cheap!
SLS: Myths and Facts
Search the Internet and you’ll find lots of claims that SLS is carcinogenic (causes cancer). The fact is there is no evidence that using SLS leads to cancer. However, there is a strong body of medical research that shows SLS is a definite skin irritant and an environmental toxin.
In summary, sodium lauryl sulfate can cause
- Moderate to severe skin irritation
- Degeneration of cell membranes
- Skin corrosion (10%-30% SLS solution)
- Cornea damage (10% SLS solution)
- Hair loss
- Significant number of blackheads and acne (1%-5% SLS solution)
- Depression, labored breathing, diarrhea and even death in some animals (15% SLS solution)
Interestingly both many products recommended by GPs and doctors commonly used by patients with skin issues, claim to “non-comedogenic” yet they both contain SLS which is proven to be comedogenic at just 1% concentration! That is why we should never take the baseless claims for granted. Always read the ingredients and not just believe the unregulated marketing nonsense.
Hair loss and acne are of concern to many, but still these are mainly cosmetic concerns. What I find most disturbing about SLS is that it is corrosive and degenerates cell membranes. Our skin is our body’s largest protective barrier against infection. Because SLS denatures protein, it causes our skin to become more vulnerable to penetration and absorption of foreign irritants. This is one cause of eczema and other sensitive skin problems.
What Can You Do?
Step one, check the ingredients of your soap products for sodium lauryl sulfate or sodium laureth sulfate.
Step two, if it contains either chemical, take action! Do yourself and your family a favour – switch to a soap and shampoo that is SLS free at our soap shop.
Step three, share this information with people you care about and help them save their skin and long term health!
Abstracts from medical journals (points in bold are in the summary above):
“In concentrations of 2% to 5%, Sodium lauryl sulfate causes irritating or sensitizing reactions in many of people” (1).
“Although Sodium Lauryl Sulfate is not carcinogenic in experimental animals, it has been shown that it causes severe epidermal changes to the area of the skin of mice to which it was applied. This study indicates a need for tumor-enhancing activity assays.
Auto radiographic studies of rat skin treated with radio-labeled Sodium Lauryl Sulfate found heavy deposition of the detergent on the skin surface and in the hair follicles; damage to the hair follicle could result from such deposition. Further, it has been reported that 1 percent and 5 percent Sodium Lauryl Sulfate produced significant number of comedones when applied to the pinna of albino rabbits. These two problems – possible hair loss and comedone* formation – along with proven irritancy, should be considered in the formulation of cosmetic products” (2) (*A comedone is the medical term for a blocked pore or what we commonly refer to as blackheads or whiteheads. When a comedone is inflamed, it’s what we call acne)
Here’s an abstract from the International Journal of ToxicologyDecember 1983 vol. 2 no. 7 127-181:
“Sodium and Ammonium Lauryl Sulfate are anionic surfactants used in cosmetics as cleansing agents. In absorption, metabolism, and excretion studies, Sodium Lauryl Sulfate had a degenerative effect on the cell membranes because of its protein denaturing properties. Low levels of skin penetration may occur at high use concentration.
Sodium Lauryl Sulfate had an LD50 of 0.8 to 1.10 g/kg in rats. A formulation containing 15% Ammonium Lauryl Sulfate caused depression, labored breathing, diarrhea, and death in four out of 20 animals.
In acute ocular tests, 10% Sodium Lauryl Sulfate caused corneal damage to the rabbits’ eyes if not irrigated, or if irrigation was delayed. A Draize test of a product containing 5.1% Sodium Lauryl Sulfate caused mild irritation, and products containing 21% detergent were severely irritating with no rinse, and mildly irritating when rinsed. Ammonium Lauryl Sulfate solutions containing 1.25%-27.4% detergent showed increasing irritation with increasing concentration; rinsing decreased irritation.
Acute animal skin irritation studies of 0.5%-10% Sodium Lauryl Sulfate caused slight to moderate irritation. Applications of 10%-30% detergent caused skin corrosion and severe irritation. Solutions of 2%, 10%, and 20% Ammonium Lauryl Sulfate were highly irritating and dangerous. One percent and 5% Sodium Lauryl Sulfate produced a significant number of comedones when applied to the pinna** of albino rabbits.” (**the pinna is the outer ear)
(1) European Journal of Dermatology, September-October 2001, pages 416-419; American Journal of Contact Dermatitis, March 2001, pages 28–32
(2) Journal of the American College of Toxicology, Volume 2, Number 7, pp. 127-181, 1983